Interesting statement, but not true. Have a look at this:
https://www.washingtonpost.com/outlo...re-socialists/
You realize that Hitlers party (the Nazis - i.e. so called National Socialists) incarcerated and often killed hundreds of thousand of Socialists? That the Nazis have been funded by the rich industrialists and supported by the people who wanted the German emperor back? Not a left wing party. Just populist, right wing and evil.
Hitler attracted the same kind of people like Trump (and any other populist despot) later on - and he used the same methods - making up big lies and finding people dumb enough to believe them.
Of course, if you consider e.g. Trump, Johnson and Bolsonaro as "left wing", than yes, this is what Hitler was as well :p;